Question

我正在尝试创建一个我之前已经完成的ExpandableListView，并且我知道它会回收视图，但我试图让视图成为最终的而不是更改。当我选择组视图以展开视图时，组视图有时会更改为另一个组视图的文本。

请有人看看我的代码，看看我做错了什么。

public class ClientListAdapter extends BaseExpandableListAdapter 
{
private Context context;
private List<Client> listOfClients;

public ClientListAdapter(Context context, List<Client> listOfClients)
{
    this.context = context;
    this.listOfClients = listOfClients;
}

private static class ViewHolder
{
    TextView name;
    TextView ID;
    TextView email;
    TextView phoneNumber;
    Button writeToNFC;
}

@Override
public int getGroupCount() 
{
    return listOfClients.size();
}

@Override
public int getChildrenCount(int groupPosition) 
{
    return 1; // There will only ever be 1 child in the group.
}

@Override
public Object getGroup(int groupPosition) 
{
    return groupPosition;
}

@Override
public Object getChild(int groupPosition, int childPosition) 
{
    return null;
}

@Override
public long getGroupId(int groupPosition) 
{
    return groupPosition;
}

@Override
public long getChildId(int groupPosition, int childPosition) 
{
    return groupPosition;
}

@Override
public boolean hasStableIds() 
{
    return true; // Stops child views from resetting.
}

@Override
public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) 
{
    final ViewHolder viewHolder;

    if(convertView == null)
    {
        LayoutInflater layoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = layoutInflater.inflate(R.layout.unexpanded, parent, false);

        viewHolder = new ViewHolder();
        viewHolder.name = (TextView) convertView.findViewById(R.id.ClientName);

        viewHolder.name.setText(listOfClients.get(groupPosition).getName());

        System.out.println("Group name: " + listOfClients.get(groupPosition).getName());

        convertView.setTag(viewHolder);
    }
    else
    {
        viewHolder = (ViewHolder) convertView.getTag();
    }

    return convertView;
}

@Override
public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) 
{
    final ViewHolder viewHolder;

    if(convertView == null)
    {
        LayoutInflater layoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = layoutInflater.inflate(R.layout.client_details, parent, false);

        viewHolder = new ViewHolder();

        convertView.setTag(viewHolder);
    }
    else
    {
        viewHolder = (ViewHolder) convertView.getTag();
    }

    viewHolder.ID = (TextView) convertView.findViewById(R.id.ClientID);
    viewHolder.email = (TextView) convertView.findViewById(R.id.ClientEmail);
    viewHolder.phoneNumber = (TextView) convertView.findViewById(R.id.ClientTel);
    viewHolder.writeToNFC = (Button) convertView.findViewById(R.id.WriteToNFC);

    viewHolder.ID.setText(listOfClients.get(groupPosition).getClientID());
    viewHolder.email.setText(listOfClients.get(groupPosition).getEmail());
    viewHolder.phoneNumber.setText(listOfClients.get(groupPosition).getPhoneNumber());

    viewHolder.writeToNFC.setOnClickListener(new OnClickListener() 
    {
        @Override
        public void onClick(View v) 
        {
            MainActivity mainActivity = (MainActivity) context;

            String ndefMessage = viewHolder.ID.getText().toString();

            mainActivity.setNdefMessage(ndefMessage);

            Toast.makeText(context, "Client details selected.", Toast.LENGTH_SHORT).show();

            System.out.println("NDEF message: " + ndefMessage);
        }
    });

    System.out.println("Group position: " + groupPosition);
    System.out.println("Child position: " + childPosition);

    return convertView;
}

@Override
public boolean isChildSelectable(int groupPosition, int childPosition) 
{
    return false;
}

}

Answer 1

我实际上只是设法修复错误。我必须做的是将viewHolder.name函数放在if语句之外，如下所示：

@Override
public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) 
{
    final ViewHolder viewHolder;

    if(convertView == null)
    {
        LayoutInflater layoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = layoutInflater.inflate(R.layout.unexpanded, parent, false);

        viewHolder = new ViewHolder();

        System.out.println("Group name: " + listOfClients.get(groupPosition).getName());

        convertView.setTag(viewHolder);
    }
    else
    {
        viewHolder = (ViewHolder) convertView.getTag();
    }

    viewHolder.name = (TextView) convertView.findViewById(R.id.ClientName);

    viewHolder.name.setText(listOfClients.get(groupPosition).getName());

    return convertView;
}

Answer 2

使用以下覆盖BaseExpandableListAdapter

中的方法

public int getChildType(int groupPosition, int childPosition) {
//define a condition here to differentiate between your child views.
}

public int getChildTypeCount() {
    return 2; <-- this is the number of views for your child
}

希望这会有所帮助。

在Android中选择后，ExpandableListView组视图会发生更改

2 个答案: